In an image captured by an imaging device there is a limited range of bright and dark information that can be captured. The difference between the brightest detail and the darkest detail that can be captured by an imager without clipping is known as the dynamic range of light. Digital cameras have a much more limited ability to capture the dynamic range compared to the human eye (the human eyes can see ˜24 stops of light compared to ˜10 for a digital SLR and ˜6 for a point and shoot camera).
Video imaging systems may make a tradeoff between showing the brightest, darkest, or mid range details when selecting the exposure for a scene with high dynamic range. If an exposure is set for bright details then shadows are clipped and vice versa.
High-end sensors can improve the dynamic range of a video imaging system, but only by a small amount (e.g. the difference in sensor quality between a point and shoot camera and a dSLR camera might only double the dynamic range).
To a limited extent, it is possible to improve dynamic range of a sensor by lowering its resolution.